F1nut - adding a 1.5 ohm resistor seems to me to be a SERIOUS mod. If we're talking speakers which drop to as low as 3 ohms or so, that's a major drop in db's, relative to what we'd expect for a typical design without the resistor, at the same gain settings.
You'll have to take that up with Bob Carver.
Also, What about the damping then? People are out there buying 4 ga. wire for their speaker runs to reduce the resistance, and improve amplifier damping control.
A lot of folks don't understand that the damping factor has no bearing as long it is above 10. The difference between a factor of 10 and 2000 is so minuet it is measured in tenths.
What shouldn't matter? Is that the question? Seems obvious enough - what shouldn't matter is where we have the volume position set on the preamp, whether it's 1/4 turn, or 1/2 turn is not important, as long as we are not asking for more voltage then the preamp can cleanly deliver. Position then is just psychological. We might think that,"hey this 300 watt amplifier isn't as powerful as my other 300 watt amplifier", just because we are turning the gain higher for the same volume.
The bottom line is where the amp starts to run out of gas. Otherwise known as clipping.
A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."